Cell-specific reference signal transmissions for evolved machine type communication

ABSTRACT

The present disclosure provides reduced cell-specific reference signal (CRS) transmissions for evolved machine type communication (eMTC). In one aspect, a network entity may determine at least one narrow band for transmission of a CRS. The network entity may further identify one or more resource blocks proximate the at least one narrow band and transmit the CRS on the narrow band and the one or more proximate resource blocks to a UE. In another aspect, a UE may apply a receive window to filter one or more noise samples outside at least one narrow band allocation, the receive window corresponding to one or more resource blocks located outside the defined number of resource blocks of the at least one narrow band allocation. The UE may further receive the CRS within the at least one narrow band allocation from a network entity in response to applying the receive window.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. Non-Provisional applicationSer. No. 15/961,329, entitled CELL-SPECIFIC REFERENCE SIGNALTRANSMISSIONS FOR EVOLVED MACHINE TYPE COMMUNICATION and filed on Apr.24, 2018, which claims the benefit of U.S. Provisional Application Ser.No. 62/512,525, entitled “CELL-SPECIFIC REFERENCE SIGNAL TRANSMISSIONSFOR EVOLVED MACHINE TYPE COMMUNICATION” and filed on May 30, 2017, bothof which are expressly incorporated by reference herein in theirentirety.

BACKGROUND

Aspects of the present disclosure relate generally to wirelesscommunication networks, and more particularly, to transmissions ofcell-specific reference signals (CRS) in an evolved machine typecommunication (eMTC) environment.

Wireless communication networks are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems, orthogonalfrequency-division multiple access (OFDMA) systems, and single-carrierfrequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. For example, a fifth generation (5G)wireless communications technology (which can be referred to as newradio (NR)) is envisaged to expand and support diverse usage scenariosand applications with respect to current mobile network generations. Inan aspect, 5G communications technology can include: enhanced mobilebroadband addressing human-centric use cases for access to multimediacontent, services and data; ultra-low latency (ULL) and/orultra-reliable-low latency communications (URLLC) with certainspecifications for latency and reliability; and massive machine typecommunications, which can allow a very large number of connected devicesand transmission of a relatively low volume of non-delay-sensitiveinformation. As the demand for mobile broadband access continues toincrease, however, further improvements in NR communications technologyand beyond may be desired.

For example, for NR communications technology and beyond, reduced CRSmay inhibit a desired level of speed or customization for efficientoperation. Thus, improvements in wireless communication operations maybe desired.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In an aspect, the present disclosure includes a method for wirelesscommunications at a network entity. The described aspects may includedetermining at least one narrow band for transmission of a cell-specificreference signal (CRS) to a user equipment (UE). The described aspectsmay further include identifying one or more resource blocks proximatethe at least one narrow band. The described aspects may further includetransmitting the CRS on the narrow band and the one or more proximateresource blocks to the UE.

In another aspect, a network entity comprises a memory and at least oneprocessor in communication with the memory. The at least one processormay be configured to determine at least one narrow band for transmissionof a CRS to a UE. The at least one processor may further be configuredto identify one or more resource blocks proximate the at least onenarrow band. The at least one processor may further be configured totransmit the CRS on the narrow band and the one or more proximateresource blocks to the UE.

In an additional aspect, a network entity for wireless communicationsmay include means for determining at least one narrow band fortransmission of a CRS to a UE. The network entity may further includemeans for identifying one or more resource blocks proximate the at leastone narrow band. The network entity may further include means fortransmitting the CRS on the narrow band and the one or more proximateresource blocks to the UE.

In yet another aspect, a computer-readable medium storing computer codeexecutable by a processor for wireless communications at a networkentity may determining at least one narrow band for transmission of aCRS to a UE. The computer-readable medium may further include code foridentifying one or more resource blocks proximate the at least onenarrow band. The computer-readable medium may further include code fortransmitting the CRS on the narrow band and the one or more proximateresource blocks to the UE.

In an aspect, the present disclosure includes a method for wirelesscommunications at a user equipment. The described aspects may includereceiving at least one narrow band allocation corresponding to a numberof resource blocks allocated for CRS reception. The described aspectsmay further include applying a receive window to filter one or morenoise samples outside the at least one narrow band allocation, thereceive window corresponding to one or more resource blocks locatedoutside the defined number of resource blocks of the at least one narrowband allocation. The described aspects may further include receiving theCRS within the at least one narrow band allocation from a network entityin response to applying the receive window.

In another aspect, a UE comprises a memory and at least one processor incommunication with the memory. The at least one processor may beconfigured to receive at least one narrow band allocation correspondingto a number of resource blocks allocated for CRS reception. The at leastone processor may further be configured to apply a receive window tofilter one or more noise samples outside the at least one narrow bandallocation, the receive window corresponding to one or more resourceblocks located outside the defined number of resource blocks of the atleast one narrow band allocation. The at least one processor may furtherbe configured to receive the CRS within the at least one narrow bandallocation from a network entity in response to applying the receivewindow.

In an additional aspect, a UE may include means for receiving at leastone narrow band allocation corresponding to a number of resource blocksallocated for CRS reception. The UE may further include means forapplying a receive window to filter one or more noise samples outsidethe at least one narrow band allocation, the receive windowcorresponding to one or more resource blocks located outside the definednumber of resource blocks of the at least one narrow band allocation.The UE may further include means for receiving the CRS within the atleast one narrow band allocation from a network entity in response toapplying the receive window.

In yet another aspect, a computer-readable medium storing computer codeexecutable by a processor for wireless communications at a UE mayinclude code for receiving at least one narrow band allocationcorresponding to a number of resource blocks allocated for CRSreception. The computer-readable medium may further include code forapplying a receive window to filter one or more noise samples outsidethe at least one narrow band allocation, the receive windowcorresponding to one or more resource blocks located outside the definednumber of resource blocks of the at least one narrow band allocation.The computer-readable medium may further include code for receiving theCRS within the at least one narrow band allocation from a network entityin response to applying the receive window.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction withthe appended drawings, provided to illustrate and not to limit thedisclosed aspects, wherein like designations denote like elements, andin which:

FIG. 1 is a schematic diagram of an example of a wireless communicationnetwork including at least one base station having narrow band extensioncomponent and at least one user equipment (UE) having a narrow bandcomponent;

FIG. 2A is a graphical diagram of a power comparison for cell-specificreference signal (CRS) transmission over full bandwidth compared toreduced CRS (or narrow bandwidth);

FIG. 2B is a graphical diagram of CRS transmission degradation inperformance as a result of CRS muting;

FIG. 2C is a graphical diagram of reduced CRS without an additional‘delta’ number of resource blocks compared to reduced CRS with theadditional number of ‘delta’ resource blocks;

FIG. 2D is a graphical diagram of the performance improvement forreduced CRS having the extended number of resource blocks;

FIG. 2E is a graphical diagram of a UE operation system bandwidthwithout windowing compared to with windowing;

FIG. 2F is a graphical diagram of the CRS transmission performance alongmultiple bandwidths including at least one with windowing;

FIG. 2G is a graphical diagram of the CRS transmission performance alongmultiple bandwidths with and/or without CRS muting and/or windowing;

FIG. 2H is a graphical diagram of an aspect of reduced CRS detection;

FIG. 2I is a graphical diagram of an aspect of CRS muting detection;

FIG. 3 is a flow diagram of an example of a method of wirelesscommunication at a network entity;

FIG. 4 is a flow diagram of an example of a method of wirelesscommunication at a UE;

FIG. 5 is a schematic diagram of example components of the UE of FIG. 1;and

FIG. 6 is a schematic diagram of example components of the base stationof FIG. 1.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that such aspect(s) maybe practiced without these specific details. Additionally, the term“component” as used herein may be one of the parts that make up asystem, may be hardware, firmware, and/or software stored on acomputer-readable medium, and may be divided into other components.

The present disclosure generally relates to cell-specific referencesignal (CRS) transmissions in an evolved machine type communication(eMTC) system. Specifically, a network entity may transmit a CRS on adownlink communication channel to a user equipment (UE) within a narrowband allocation. The UE may utilize the received CRS for cell searchand/or initial acquisition, downlink channel estimation for coherentdemodulation/detection at the UE, and/or downlink channel qualitymeasurements. In some eMTC networks, CRS transmissions may be reduced tospecific narrow bands corresponding to a number of resource blocks so asto reduce interference between adjacent cells, for example. In an eMTCnetwork, for instance, a UE may monitor CRS on at least one configuredor scheduled narrow band. Further, on the subframes where the UE maypotentially monitor MTC physical downlink control channel (MPDCCH)and/or the physical downlink shared channel (PDSCH), the network maymute the CRS outside the region of interest, or more specifically,outside the narrow bands. However, by reducing CRS transmissions (e.g.,or the bandwidth available for CRS transmissions), UEs that typicallyprocess the CRS over an entire bandwidth may potentially experienceperformance degradations when receiving CRS transmissions from a networkentity. Hence, mitigation of performance degradation as a result of CRSreductions may be desirable in eMTC systems.

As such, the present aspects may provide CRS transmissions in eMTCsystems. For example, in an aspect, a network entity may determine atleast one narrow band for transmission of a CRS to a UE. The networkentity may further identify one or more resource blocks proximate to theat least one narrow band and transmit the CRS on the narrow band and theone or more proximate tp resource blocks to the UE. Additionally, in anaspect, a UE may receive at least one narrow band allocationcorresponding to a number of resource blocks allocated for CRSreception. Further, the UE may apply a receive window to filter one ormore noise samples outside the at least one narrow band allocation andreceive the CRS within the at least one narrow band allocation from anetwork entity.

Additional features of the present aspects are described in more detailbelow with respect to FIGS. 1-6.

It should be noted that the techniques described herein may be used forvarious wireless communication networks such as CDMA, TDMA, FDMA, OFDMA,SC-FDMA, and other systems. The terms “system” and “network” are oftenused interchangeably. A CDMA system may implement a radio technologysuch as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0and A are commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856)is commonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data(HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants ofCDMA. A TDMA system may implement a radio technology such as GlobalSystem for Mobile Communications (GSM). An OFDMA system may implement aradio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA(E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal MobileTelecommunication System (UMTS). 3GPP Long Term Evolution (LTE) andLTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA,E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from anorganization named “3rd Generation Partnership Project” (3GPP). CDMA2000and UMB are described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). The techniques describedherein may be used for the systems and radio technologies mentionedabove as well as other systems and radio technologies, includingcellular (e.g., LTE) communications over a shared radio frequencyspectrum band. The description below, however, describes an LTE/LTE-Asystem for purposes of example, and LTE terminology is used in much ofthe description below, although the techniques are applicable beyondLTE/LTE-A applications (e.g., to 5G networks or other next generationcommunication systems).

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

Referring to FIG. 1, in accordance with various aspects of the presentdisclosure, an example wireless communication network 100 may include atleast one UE 110 with a modem 140 having a narrow band component 150that may apply a receive window 152 to filter out noise samples outsidethe narrow band 172 and/or a central number of resource blocks. In otherwords, to address the performance gap (e.g., especially at very lowsignal-to-noise ratios (SNR)) between the UE 110 processing over areduced or narrow bandwidth and the UE 110 processing the full systembandwidth, the noise samples from the remaining bandwidth may bedetected and filtered out when receiving a CRS 174 on a narrow band 172.

Additionally, the narrow band component 150 may be configured, via areduced CRS detection component 154, to detect a reduced CRS 174transmission from the base station 105. For example, in an aspect, theCRS detection component 154 may be configured to perform time domainprocessing for one or more narrow bands located outside the narrow band172 of interest and/or the central resource blocks to detect whether CRS174 muting is applied. In another aspect, the CRS detection component154 may be configured to determine, semi-statically, whether the basestation 105 (or network) has deployed reduced CRS 174 transmissions.

Wireless communication network 100 may also include at least one basestation 105 with a modem 160 having a narrow band extension component170 that may allocate extended resource blocks 176 for CRS 174transmissions on the narrow band 172 as well as the extended resourceblocks 176. That is, to improve the CRS processing gain for channelestimation, the narrow band extension component 170 may allocate theextended resource blocks 176 to one or both sides of the narrow band 172for CRS 174 transmissions on a wider range of resource blocks.

The wireless communication network 100 may include one or more basestations 105, one or more UEs 110, and a core network 115. The corenetwork 115 may provide user authentication, access authorization,tracking, internet protocol (IP) connectivity, and other access,routing, or mobility functions. The base stations 105 may interface withthe core network 115 through backhaul links 120 (e.g., S1, etc.). Thebase stations 105 may perform radio configuration and scheduling forcommunication with the UEs 110, or may operate under the control of abase station controller (not shown). In various examples, the basestations 105 may communicate, either directly or indirectly (e.g.,through core network 115), with one another over backhaul links 125(e.g., X1, etc.), which may be wired or wireless communication links.

The base stations 105 may wirelessly communicate with the UEs 110 viaone or more base station antennas. Each of the base stations 105 mayprovide communication coverage for a respective geographic coverage area130. In some examples, base stations 105 may be referred to as a basetransceiver station, a radio base station, an access point, an accessnode, a radio transceiver, a NodeB, eNodeB (eNB), gNodeB (gNB), HomeNodeB, a Home eNodeB, a relay, or some other suitable terminology. Thegeographic coverage area 130 for a base station 105 may be divided intosectors or cells making up only a portion of the coverage area (notshown). The wireless communication network 100 may include base stations105 of different types (e.g., macro base stations or small cell basestations, described below). Additionally, the plurality of base stations105 may operate according to different ones of a plurality ofcommunication technologies (e.g., 5G (New Radio or “NR”), fourthgeneration (4G)/LTE, 3G, Wi-Fi, Bluetooth, etc.), and thus there may beoverlapping geographic coverage areas 130 for different communicationtechnologies.

In some examples, the wireless communication network 100 may be orinclude one or any combination of communication technologies, includinga new radio (NR) or 5G technology, a Long Term Evolution (LTE) orLTE-Advanced (LTE-A) or MuLTEfire technology, a Wi-Fi technology, aBluetooth technology, or any other long or short range wirelesscommunication technology. In LTE/LTE-A/MuLTEfire networks, the termevolved node B (eNB) may be generally used to describe the base stations105, while the term UE may be generally used to describe the UEs 110.The wireless communication network 100 may be a heterogeneous technologynetwork in which different types of eNBs provide coverage for variousgeographical regions. For example, each eNB or base station 105 mayprovide communication coverage for a macro cell, a small cell, or othertypes of cell. The term “cell” is a 3GPP term that can be used todescribe a base station, a carrier or component carrier associated witha base station, or a coverage area (e.g., sector, etc.) of a carrier orbase station, depending on context.

A macro cell may generally cover a relatively large geographic area(e.g., several kilometers in radius) and may allow unrestricted accessby UEs 110 with service subscriptions with the network provider.

A small cell may include a relative lower transmit-powered base station,as compared with a macro cell, that may operate in the same or differentfrequency bands (e.g., licensed, unlicensed, etc.) as macro cells. Smallcells may include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs 110 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessand/or unrestricted access by UEs 110 having an association with thefemto cell (e.g., in the restricted access case, UEs 110 in a closedsubscriber group (CSG) of the base station 105, which may include UEs110 for users in the home, and the like). A micro cell may cover ageographic area larger than a pico cell and a femto cell, but smallerthan a macro cell. An eNB for a macro cell may be referred to as a macroeNB. An eNB for a small cell may be referred to as a small cell eNB, apico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple(e.g., two, three, four, and the like) cells (e.g., component carriers).

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack and data in the user plane may be based onthe IP. A user plane protocol stack (e.g., packet data convergenceprotocol (PDCP), radio link control (RLC), MAC, etc.), may performpacket segmentation and reassembly to communicate over logical channels.For example, a MAC layer may perform priority handling and multiplexingof logical channels into transport channels. The MAC layer may also usehybrid automatic repeat/request (HARQ) to provide retransmission at theMAC layer to improve link efficiency. In the control plane, the RRCprotocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 110 and the base station 105. The RRCprotocol layer may also be used for core network 115 support of radiobearers for the user plane data. At the physical (PHY) layer, thetransport channels may be mapped to physical channels.

The UEs 110 may be dispersed throughout the wireless communicationnetwork 100, and each UE 110 may be stationary or mobile. A UE 110 mayalso include or be referred to by those skilled in the art as a mobilestation, a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable terminology. A UE 110 may be a cellular phone, asmart phone, a personal digital assistant (PDA), a wireless modem, awireless communication device, a handheld device, a tablet computer, alaptop computer, a cordless phone, a smart watch, a wireless local loop(WLL) station, an entertainment device, a vehicular component, acustomer premises equipment (CPE), or any device capable ofcommunicating in wireless communication network 100. Additionally, a UE110 may be Internet of Things (IoT) and/or machine-to-machine (M2M) typeof device, e.g., a low power, low data rate (relative to a wirelessphone, for example) type of device, that may in some aspects communicateinfrequently with wireless communication network 100 or other UEs. A UE110 may be able to communicate with various types of base stations 105and network equipment including macro eNBs, small cell eNBs, macro gNBs,small cell gNBs, relay base stations, and the like.

UE 110 may be configured to establish one or more wireless communicationlinks 135 with one or more base stations 105. The wireless communicationlinks 135 shown in wireless communication network 100 may carry uplink(UL) transmissions from a UE 110 to a base station 105, or downlink (DL)transmissions, from a base station 105 to a UE 110. The downlinktransmissions may also be called forward link transmissions while theuplink transmissions may also be called reverse link transmissions. Eachwireless communication link 135 may include one or more carriers, whereeach carrier may be a signal made up of multiple sub-carriers (e.g.,waveform signals of different frequencies) modulated according to thevarious radio technologies described above. Each modulated signal may besent on a different sub-carrier and may carry control information (e.g.,reference signals, control channels, etc.), overhead information, userdata, etc. In an aspect, the wireless communication links 135 maytransmit bidirectional communications using frequency division duplex(FDD) (e.g., using paired spectrum resources) or time division duplex(TDD) operation (e.g., using unpaired spectrum resources). Framestructures may be defined for FDD (e.g., frame structure type 1) and TDD(e.g., frame structure type 2). Moreover, in some aspects, the wirelesscommunication links 135 may represent one or more broadcast channels.

In some aspects of the wireless communication network 100, base stations105 or UEs 110 may include multiple antennas for employing antennadiversity schemes to improve communication quality and reliabilitybetween base stations 105 and UEs 110. Additionally or alternatively,base stations 105 or UEs 110 may employ multiple input multiple output(MIMO) techniques that may take advantage of multi-path environments totransmit multiple spatial layers carrying the same or different codeddata.

Wireless communication network 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or multi-carrier operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 110 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both FDD and TDD component carriers. Thebase stations 105 and UEs 110 may use spectrum up to Y MHz (e.g., Y=5,10, 15, or 20 MHz) bandwidth per carrier allocated in a carrieraggregation of up to a total of Yx MHz (x=number of component carriers)used for transmission in each direction. The carriers may or may not beadjacent to each other. Allocation of carriers may be asymmetric withrespect to DL and UL (e.g., more or less carriers may be allocated forDL than for UL). The component carriers may include a primary componentcarrier and one or more secondary component carriers. A primarycomponent carrier may be referred to as a primary cell (PCell) and asecondary component carrier may be referred to as a secondary cell(SCell).

The wireless communications network 100 may further include basestations 105 operating according to Wi-Fi technology, e.g., Wi-Fi accesspoints, in communication with UEs 110 operating according to Wi-Fitechnology, e.g., Wi-Fi stations (STAs) via communication links in anunlicensed frequency spectrum (e.g., 5 GHz). When communicating in anunlicensed frequency spectrum, the STAs and AP may perform a clearchannel assessment (CCA) or listen before talk (LBT) procedure prior tocommunicating in order to determine whether the channel is available.

Additionally, one or more of base stations 105 and/or UEs 110 mayoperate according to a NR or 5G technology referred to as millimeterwave (mmW or mmwave) technology. For example, mmW technology includestransmissions in mmW frequencies and/or near mmW frequencies. Extremelyhigh frequency (EHF) is part of the radio frequency (RF) in theelectromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and awavelength between 1 millimeter and 10 millimeters. Radio waves in thisband may be referred to as a millimeter wave. Near mmW may extend downto a frequency of 3 GHz with a wavelength of 100 millimeters. Forexample, the super high frequency (SHF) band extends between 3 GHz and30 GHz, and may also be referred to as centimeter wave. Communicationsusing the mmW and/or near mmW radio frequency band has extremely highpath loss and a short range. As such, base stations 105 and/or UEs 110operating according to the mmW technology may utilize beamforming intheir transmissions to compensate for the extremely high path loss andshort range.

FIG. 2A is a graphical diagram of a power comparison for CRStransmission over full bandwidth compared to reduced CRS (or narrowbandwidth). The left column includes graphical representations oftransmit CRS power, noise power, and received power for transmission ofCRS over full bandwidth 202. The right column includes transmit CRSpower, noise power, and received power for transmission of reduced CRS204. In the illustrated aspects, transmission of CRS over full bandwidth202 is generally made at a consistent power level across the systembandwidth. However, with reduced CRS 204 transmissions, the transmit CRSpower is correspondingly reduced, yet the noise power and thecorresponding noise in the received power (e.g., for a UE) may indicatethe presence of narrow bands in resource blocks where such narrow bandsdo not exist. For example, at 206, the system bandwidth may be 50resource blocks, and the network may transmit CRS over a central 6resource blocks and eMTC on a first narrow band. At 208, a typical UEmay be interested in the first narrow band and may process the CRS fromthese resource elements. However, at 210, there may be UEs that monitora complete system bandwidth including the noise samples from otherresource elements, resulting in performance degradations.

FIG. 2B is a graphical diagram of CRS transmission degradation 212 inperformance as a result of CRS muting. The line 214 representing a 10MHz front-end (FE) bandwidth with no network entity (e.g., eNB) CRSmuting may be considered as a baseline. The FE bandwidth may be thebandwidth over which the UE 110 monitors/processes the resource blocks.Two examples of CRS muting are shown by lines 216 and 218. The line 216shows a 10 MHz FE bandwidth having network entity (e.g., eNB) CRSmuting. The line 216 demonstrates a performance degradation ofapproximately 3 dB at 10% packet error rate (PER). The line 218 shows a1.4 MHz FE bandwidth having network entity (e.g., eNB) CRS muting. Theline 218 demonstrates a performance degradation of approximately 1.5 dBat 10% PER. As such, CRS muting by the network entity (e.g., eNB) mayintroduce higher levels of noise received or detected at the UE.

FIG. 2C is a graphical diagram of reduced CRS without an additional‘delta’ number of resource blocks 220 compared to reduced CRS with theadditional number of ‘delta’ resource blocks 222. Specifically, toaddress the performance degradations as shown and described herein withrespect to FIG. 2B, the network entity may not only transmit the reducedCRS on the assigned narrow band, but also an additional number of‘delta’ resource blocks 224 on one or both adjacent sides of the narrowband. For the reduced CRS with the additional number of ‘delta’ resourceblocks 222, the system bandwidth may be 50 resource blocks where thenetwork entity may transmit the CRS over a central 6 resource blocks andan eMTC at a first narrow band. The network entity may also transmit theCRS over or on three additional resource blocks on either side of thefirst narrow band. For example, instead of transmitting the CRS on justthe narrow band of interest, the network entity (e.g., eNB) may extendthe CRS transmission by ‘delta’ number of resource blocks on one or bothsides of the narrow band. By providing additional resource blocksadjacent to the narrow band, the CRS processing gain for channelestimation may be improved, and measurement accuracies of covariancematrix (Rnn), frequency tracking loop (FTL), and time tracking loop(TTL) may be improved.

In some aspects, the ‘delta’ number of resource blocks may be dependenton a network implementation. For example, the ‘delta’ number of resourceblocks may be a pre-determined value. Further, in some aspects, the‘delta’ number of resource blocks may depend on a power factor. In someaspects, the ‘delta’ number of resource blocks may be different oneither side of the narrow band. For instance, this may occur on theedges of the bandwidth where additional resource blocks are available ononly one of the sides. In other scenarios, the additional resource blockallocation may be symmetrical.

FIG. 2D is a graphical diagram of the performance improvement 232 forreduced CRS having the extended number of resource blocks. For example,the performance improvement 232 may be obtained with the additional‘delta’ number of resource blocks at the network entity (e.g., eNB) withthe CRS muting. Specifically, for the 10 MHz FE bandwidth, theperformance gain may be approximately 1.5 dB at 10% PER with respect tono additional ‘delta’ number of resource blocks added by the networkentity. Additionally, the performance gain is comparable to the 1.4 MHzFE bandwidth.

FIG. 2E is a graphical diagram of a UE operation system bandwidthwithout windowing compared to with windowing. A performance gap may beseen (e.g., especially at very low SNRs) between a UE processing over1.4 MHz bandwidth and a UE processing full system bandwidth (e.g., aloss of 1.5 dB may be seen in FIG. 2B). In order to close this gap, a UEmay switch to the 1.4 MHz bandwidth and filter out the noise from therest of the bandwidth. However, such procedure may underutilize thepotential performance gain when the network does not employ reducedbandwidth (e.g., no gain of 1.5 dB in FIG. 2B). For instance, a power onthe CRS resource elements across the system bandwidth is shown for a UEoperation using the system bandwidth without windowing 240.Additionally, a power on the CRS resource elements across the systembandwidth is shown for a UE operation using the system bandwidth withwindowing 242. With windowing, a UE may apply a receive window so as tofilter out noise samples 244 outside the narrow band of interest and acentral six (6) resource blocks. Compared to the 1.4 MHz systembandwidth, the CRS processing gain may increase by at least 1.75 dB(e.g., factor of 18/12). If the network provides an additional ‘delta’resource blocks on either side of the narrow band of interest, then theCRS processing gain may be at least 3 dB (e.g., factor of 24/12).

FIG. 2F is a graphical diagram of the CRS transmission performance 250along multiple bandwidths including at least one with windowing. Forexample, a line 258 representing a 10 MHz FE bandwidth with no networkentity (e.g., eNB) CRS muting may achieve the best possible performanceat the UE. A line 252 representing a 10 MHz FE bandwidth with networkentity (e.g., eNB) CRS muting demonstrates a performance degradation of3 dB at 10% PER. Further, a line 254 representing a 1.4 MHz FE bandwidthwith network entity (e.g., eNB) CRS muting may demonstrate a performancedegradation of 1.5 dB at 10% PER. However, with windowing at the UE andretaining the FE bandwidth to 10 MHz, the performance degradation may bereduced to 1 dB, as shown by line 256.

FIG. 2G is a graphical diagram of the CRS transmission performance 260along multiple bandwidths with and/or without CRS muting and/orwindowing. In particular, even with the application of windowing at theUE, if the network does not deploy CRS muting, performance may beimproved by an additional 1.0 dB if the UE can use the full systembandwidth while also having knowledge of the CRS muting. So, there maybe a need for the UE to detect if the network entity is performing CRSmuting or not.

FIG. 2H is a graphical diagram of an aspect of reduced CRS detection.Detection may be challenging at very low signal-to-noise ratios if theUE relies solely on energy measurements on each narrow band. Forinstance, the power on the CRS resource elements across the systembandwidth is shown when the signal-to-noise ratio is 10 dB 270.Specifically, location 274 demonstrates that at high signal-to-noiseratios, energy based detections may readily indicate CRS muting.However, at very low signal-to-noise ratios, an energy level may nearlybe the same on all narrow bands and may not be used for detection, asshown at location 276 for the received power at a signal-to-noise ratiovalue of −8 dB 272.

FIG. 2I is a graphical diagram of an aspect of CRS muting detection. Atlow signal-to-noise ratios, the energy based detection in the frequencydomain may be poor. Conversely, the signal and noise energy may bereadily differentiated from the channel energy response (CER) in a lag(e.g., time) domain due to the CRS processing gain. For example, atlocation 284, even at low signal-to-noise ratios, the CER may be fairlyclean and may be detectable.

In one aspect of detecting CRS muting, instead of applying the receivewindow only on the narrow band of interest and the central six resourceblocks, the UE may perform the lag domain processing for all othernarrow bands to detect if CRS muting is applied or not. The detectionmay be based on a lag domain signal-to-noise ratio metric. In someaspects, the metric may be determined according to:

${SNR}_{TD} = \frac{{sum}\mspace{11mu} \left( {{Highest}\mspace{14mu} N\mspace{14mu} {Terms}\mspace{14mu} {from}\mspace{14mu} {CER}} \right)}{{average}\mspace{11mu} \left( {{Lowest}\mspace{14mu} M\mspace{14mu} {Terms}\mspace{14mu} {from}\mspace{14mu} {CER}} \right)}$

If the metric (SNR_(TD)) satisfies a threshold (e.g., is less than orequal to), the UE may determine that the CRS is muted and may apply afilter to zero out the noise from the narrow band. If the metric(SNR_(TD)) does not satisfy the threshold, the UE may nonethelessconsider the narrow band for CRS processing. In some aspects, the metric(SNR_(TD)) may be modified to suit the application of the receivewindow.

In another aspect, the previous aspect of detecting CRS muting may bedifficult for UE implementation due to complexity. The UE may have tocompute multiple lag domain CERs (e.g., for 10 MHz, there may be 8narrow bands of interest). Alternatively, the UE may determine (e.g.,semi-statically) if the network is deploying reduced CRS or not. Forexample, if the UE determines that there is no CRS muting, then the UEmay not employ any windowing on the receive side. However, if the UEdetermines that there is CRS muting, then the UE may employ windowingonly on the narrow band of interest and the central six resource blocks.

Specifically, to detect CRS muting according to this aspect (e.g.,semi-statically), the UE may determine a signal-to-noise ratio metric(SNR_(TD_NoWindow)) over the entire system bandwidth, yet withoutwindowing. The UE may additionally determine a similar metric(SNR_(TD_window)) with windowing and over the entire system bandwidth.The UE may then compare an overall metric (SNR_(TD) _(Window) −SNR_(TD)_(NoWindow) ) against a threshold. If the overall metric satisfies(e.g., is greater than or equal to) the threshold, the UE may determinethat CRS muting exists. However, if the overall metric does not satisfy(e.g., is less than or equal to) the threshold, the UE may determinethat CRS muting does not exist. The forgoing procedure may not run onall the system frames (SFs). For example, the forgoing procedure may beperformed just after network acquisition and/or cellreselection/handovers. Also, the forgoing procedure may be repeated onceevery “P” milliseconds, where “P” may be a whole number.

Referring to FIG. 3, for example, a method 300 of wireless communicationin operating a network entity such as base station 105 according to theabove-described aspects to provide an extended narrow band for CRStransmissions in an eMTC environment includes one or more of theherein-defined actions.

At block 302, the method 300 may determine at least one narrow band fortransmission of a CRS to a UE. For example, in an aspect, base station105 may execute narrow band extension component 170 to determine atleast one narrow band 172 for transmission of a CRS 172 to a UE 110. Insome aspects, the at least one narrow band 172 may correspond to adefined number of resource blocks allocated for CRS 172 transmission.

At block 304, the method 300 may identify one or more resource blocksproximate to the at least one narrow band. For example, in an aspect,base station 105 may execute narrow band extension component 170 toidentify one or more resource blocks proximate to the at least onenarrow band 172. In some aspects, the one or more proximate resourceblocks may be adjacent to the defined number of resource blocks formingthe narrow band 172. In some aspects, the one or more proximate resourceblocks may be adjacent to the defined number of resource blocks on atleast one side of the at least one narrow band 172. In some aspects, thenarrow band 172 can be expanded to have resource blocks in the front,back, or both with respect to the narrow band 172. In some aspects, asize of the one or more proximate resource blocks may be based on a sizeof the narrow band 172 and/or a power factor associated with the narrowband 172 transmission.

At block 306, the method 300 may transmit the CRS on the at least onenarrow band and the one or more proximate resource blocks to the UE. Forexample, in an aspect, base station 105 may execute modem 160 totransmit the CRS 174 on the at least one narrow band 172 and the one ormore proximate resource blocks to the UE 110 on a downlink channel.

Referring to FIG. 4, for example, a method 400 of wireless communicationin operating UE 110 according to the above-described aspects to apply areceive window 152 in order to filter noise samples from outside thenarrow band 172 includes one or more of the herein-defined actions.

At block 402, the method 400 may receive at least one narrow bandallocation corresponding to a defined number of resource blocksallocated for CRS reception. For example, the UE 110 and/or modem 140may execute narrow band component 150 to receive at least one narrowband 172 allocation corresponding to a defined number of resource blocksallocated for CRS 174 reception. In some aspects, the at least onenarrow band 172 allocation may include a narrow band having a definednumber of resource blocks and one or more proximate resource blocksallocated by the network entity as described above with respect to FIG.2. In some aspects, the one or more proximate resource blocks may beadjacent to the define number of resource blocks on at least one side ofthe narrow band 172.

At block 404, the method 400 may apply a receive window to filter one ormore noise samples outside the at least one narrow band allocation, thereceive window corresponding to one or more resource blocks locatedoutside the number of resource blocks of the at least one narrow bandallocation. For instance, the UE 110 and/or modem 140 may execute narrowband component 150 to apply a receive window 152 to filter one or morenoise samples outside the at least one narrow band 172 allocation, thereceive window 152 corresponding to one or more resource blocks locatedoutside the number of resource blocks of the at least one narrow band172 allocation. In some aspects, applying the receive window 152 tofilter the one or more noise samples outside the at least one narrowband allocation may include applying the receive window 152 to a centralnumber of resource blocks in addition to the at least one narrow band172 allocation.

At block 406, the method 400 may detect the CRS within the at least onenarrow band allocation from a network entity in response to applying thereceive window. For example, the UE 110 and/or modem 140 may executenarrow band component 150 to detect the CRS 174 within the at least onenarrow band 172 allocation from a network entity in response to applyingthe receive window 152.

In some aspects, although not shown, method 400 may determine, via thenarrow band component 150, a quality metric for one or more narrow bandsover an entire bandwidth and not including the at least one narrow bandallocation, determine, via the narrow band component 150, whether thequality metric satisfies a quality metric threshold, apply, via thenarrow band component 150, a filter to zero out and/or reduce one ormore noise samples from the at least one narrow band allocation based ondetermining that the quality metric satisfies a quality metricthreshold, and identify, via the narrow band component 150, the at leastone narrow band allocation for CRS determination based on determiningthat the quality metric does not satisfy a quality metric threshold.

In some aspects, the quality metric may correspond to a signal-to-noiseratio metric and is associated with a time domain. In some aspects,identifying the at least one narrow band allocation for CRSdetermination may include forgoing application of the filter to zero outthe one or more noise samples from the at least one narrow bandallocation.

In some aspects, although not shown, method 400 may determine, via thenarrow band component 150, a first quality metric for one or more narrowbands over an entire bandwidth and not including the at least one narrowband allocation, determine, via the narrow band component 150, a secondquality metric for the one or more narrow bands over the entirebandwidth, the first and second quality metrics associated with a timedomain, determine, via the narrow band component 150, whether the firstquality metric and the second quality metric satisfy a quality metricthreshold, indicating CRS muting based on determining that the firstquality metric and the second quality metric satisfy the quality metricthreshold, and indicate, via the narrow band component 150, a lack ofCRS muting based on determining that the first quality metric and thesecond quality metric do not satisfy the quality metric threshold.

In some aspects, the first quality metric may be determined withoutapplying the receive window over the entire bandwidth and the secondquality metric may be determined by applying the receive window over theentire bandwidth. In some aspects, although not shown, method 400 mayfurther perform selection or reselection of the network entity, wherethe first quality metric and the second quality metric are determinedafter performing selection or reselection of the network entity.

Referring to FIG. 5, one example of an implementation of UE 110 mayinclude a variety of components, some of which have already beendescribed above, but including components such as one or more processors512 and memory 516 and transceiver 502 in communication via one or morebuses 544, which may operate in conjunction with modem 140 and narrowband component 150 as described herein. Further, the one or moreprocessors 512, modem 514, memory 516, transceiver 502, radio frequency(RF) front end 588 and one or more antennas 565, may be configured tosupport voice and/or data calls (simultaneously or non-simultaneously)in one or more radio access technologies. In some aspects, the modem 514may be the same as or similar to the modem 140.

In an aspect, the one or more processors 512 can include a modem 514that uses one or more modem processors. The various functions related toresource identification component 150 may be included in modem 140and/or processors 512 and, in an aspect, can be executed by a singleprocessor, while in other aspects, different ones of the functions maybe executed by a combination of two or more different processors. Forexample, in an aspect, the one or more processors 512 may include anyone or any combination of a modem processor, or a baseband processor, ora digital signal processor, or a transmit processor, or a receiverprocessor, or a transceiver processor associated with transceiver 502.In other aspects, some of the features of the one or more processors 512and/or modem 140 associated with resource identification component 150may be performed by transceiver 502.

Also, memory 516 may be configured to store data used herein and/orlocal versions of applications 575 or resource identification component150 and/or one or more of its subcomponents being executed by at leastone processor 512. Memory 516 can include any type of computer-readablemedium usable by a computer or at least one processor 512, such asrandom access memory (RAM), read only memory (ROM), tapes, magneticdiscs, optical discs, volatile memory, non-volatile memory, and anycombination thereof. In an aspect, for example, memory 516 may be anon-transitory computer-readable storage medium that stores one or morecomputer-executable codes defining resource identification component 150and/or one or more of its subcomponents, and/or data associatedtherewith, when UE 110 is operating at least one processor 512 toexecute resource identification component 150 and/or one or more of itssubcomponents.

Transceiver 502 may include at least one receiver 506 and at least onetransmitter 508. Receiver 506 may include hardware, firmware, and/orsoftware code executable by a processor for receiving data, the codecomprising instructions and being stored in a memory (e.g.,computer-readable medium). Receiver 506 may be, for example, a RFreceiver. In an aspect, receiver 506 may receive signals transmitted byat least one base station 105. Additionally, receiver 506 may processsuch received signals, and also may obtain measurements of the signals,such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. Transmitter508 may include hardware, firmware, and/or software code executable by aprocessor for transmitting data, the code comprising instructions andbeing stored in a memory (e.g., computer-readable medium). A suitableexample of transmitter 508 may include, but is not limited to, an RFtransmitter.

Moreover, in an aspect, UE 110 may include RF front end 588, which mayoperate in communication with one or more antennas 565 and transceiver502 for receiving and transmitting radio transmissions, for example,wireless communications transmitted by at least one base station 125 orwireless transmissions transmitted by UE 110. RF front end 588 may beconnected to one or more antennas 565 and can include one or morelow-noise amplifiers (LNAs) 590, one or more switches 592, one or morepower amplifiers (PAs) 598, and one or more filters 596 for transmittingand receiving RF signals.

In an aspect, LNA 590 can amplify a received signal at a desired outputlevel. In an aspect, each LNA 590 may have a specified minimum andmaximum gain values. In an aspect, RF front end 588 may use one or moreswitches 592 to select a particular LNA 590 and its specified gain valuebased on a desired gain value for a particular application.

Further, for example, one or more PA(s) 598 may be used by RF front end588 to amplify a signal for an RF output at a desired output powerlevel. In an aspect, each PA 598 may have specified minimum and maximumgain values. In an aspect, RF front end 588 may use one or more switches592 to select a particular PA 598 and a corresponding specified gainvalue based on a desired gain value for a particular application.

Also, for example, one or more filters 596 can be used by RF front end588 to filter a received signal to obtain an input RF signal. Similarly,in an aspect, for example, a respective filter 596 can be used to filteran output from a respective PA 598 to produce an output signal fortransmission. In an aspect, each filter 596 can be connected to aspecific LNA 590 and/or PA 598. In an aspect, RF front end 588 can useone or more switches 592 to select a transmit or receive path using aspecified filter 596, LNA 590, and/or PA 598, based on a configurationas specified by transceiver 502 and/or processor 512.

As such, transceiver 502 may be configured to transmit and receivewireless signals through one or more antennas 565 via RF front end 588.In an aspect, transceiver may be tuned to operate at specifiedfrequencies such that UE 110 can communicate with, for example, one ormore base stations 125 or one or more cells associated with one or morebase stations 125. In an aspect, for example, modem 140 can configuretransceiver 502 to operate at a specified frequency and power levelbased on the UE configuration of the UE 110 and the communicationprotocol used by modem 140.

In an aspect, modem 140 can be a multiband-multimode modem, which canprocess digital data and communicate with transceiver 502 such that thedigital data is sent and received using transceiver 502. In an aspect,modem 140 can be multiband and be configured to support multiplefrequency bands for a specific communications protocol. In an aspect,modem 140 can be multimode and be configured to support multipleoperating networks and communications protocols. In an aspect, modem 140can control one or more components of UE 110 (e.g., RF front end 588,transceiver 502) to enable transmission and/or reception of signals fromthe network based on a specified modem configuration. In an aspect, themodem configuration can be based on the mode of the modem and thefrequency band in use. In another aspect, the modem configuration can bebased on UE configuration information associated with UE 110 as providedby the network during cell selection and/or cell reselection.

Referring to FIG. 6, one example of an implementation of base station105 may include a variety of components, some of which have already beendescribed above, but including components such as one or more processors612, a memory 616, and a transceiver 602 in communication via one ormore buses 644, which may operate in conjunction with modem 160 andnarrow band extension component 170 to enable one or more of thefunctions described herein.

The transceiver 602, receiver 606, transmitter 608, one or moreprocessors 612, memory 616, applications 1375, buses 644, RF front end688, LNAs 690, switches 692, filters 696, PAs 698, and one or moreantennas 665 may be the same as or similar to the correspondingcomponents of UE 110, as described above, but configured or otherwiseprogrammed for base station operations as opposed to UE operations.

The above detailed description set forth above in connection with theappended drawings describes examples and does not represent the onlyexamples that may be implemented or that are within the scope of theclaims. The term “example,” when used in this description, means“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, computer-executable code or instructionsstored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with aspecially-programmed device, such as but not limited to a processor, adigital signal processor (DSP), an ASIC, a FPGA or other programmablelogic device, a discrete gate or transistor logic, a discrete hardwarecomponent, or any combination thereof designed to perform the functionsdescribed herein. A specially-programmed processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aspecially-programmed processor may also be implemented as a combinationof computing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on anon-transitory computer-readable medium. Other examples andimplementations are within the scope and spirit of the disclosure andappended claims. For example, due to the nature of software, functionsdescribed above can be implemented using software executed by aspecially programmed processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items prefaced by “at least one of” indicates a disjunctivelist such that, for example, a list of “at least one of A, B, or C”means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the common principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Furthermore, although elements of the describedaspects and/or embodiments may be described or claimed in the singular,the plural is contemplated unless limitation to the singular isexplicitly stated. Additionally, all or a portion of any aspect and/orembodiment may be utilized with all or a portion of any other aspectand/or embodiment, unless stated otherwise. Thus, the disclosure is notto be limited to the examples and designs described herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method of wireless communications at a networkentity, comprising: determining at least one narrow band fortransmission of a cell-specific reference signal (CRS) to a userequipment (UE); identifying one or more resource blocks proximate the atleast one narrow band; and transmitting the CRS on the narrow band andthe one or more proximate resource blocks to the UE.
 2. The method ofclaim 1, wherein the at least one narrow band corresponds to a definednumber of resource blocks allocated for CRS transmission.
 3. The methodof claim 2, wherein the one or more proximate resource blocks areadjacent to the defined number of resource blocks forming the narrowband.
 4. The method of claim 3, wherein the one or more proximateresource blocks are adjacent to the defined number of resource blocks onat least one side of the at least one narrow band.
 5. The method ofclaim 1, wherein a size of the one or more proximate resource blocks isbased on a power factor.
 6. A network entity, comprising: a memory; andat least one processor in communication with the memory and configuredto: determine at least one narrow band for transmission of acell-specific reference signal (CRS) to a user equipment (UE); identifyone or more resource blocks proximate the at least one narrow band; andtransmit the CRS on the narrow band and the one or more proximateresource blocks to the UE.
 7. The network entity of claim 6, wherein theat least one narrow band corresponds to a defined number of resourceblocks allocated for CRS transmission.
 8. The network entity of claim 7,wherein the one or more proximate resource blocks are adjacent to thedefined number of resource blocks forming the narrow band.
 9. Thenetwork entity of claim 8, wherein the one or more proximate resourceblocks are adjacent to the defined number of resource blocks on at leastone side of the at least one narrow band.
 10. The network entity ofclaim 6, wherein a size of the one or more proximate resource blocks isbased on a power factor.
 11. An apparatus for wireless communications,comprising: means for determining at least one narrow band fortransmission of a cell-specific reference signal (CRS) to a userequipment (UE); means for identifying one or more resource blocksproximate the at least one narrow band; and means for transmitting theCRS on the narrow band and the one or more proximate resource blocks tothe UE.
 12. The apparatus of claim 11, wherein the at least one narrowband corresponds to a defined number of resource blocks allocated forCRS transmission.
 13. The apparatus of claim 12, wherein the one or moreproximate resource blocks are adjacent to the defined number of resourceblocks forming the narrow band.
 14. The apparatus of claim 13, whereinthe one or more proximate resource blocks are adjacent to the definednumber of resource blocks on at least one side of the at least onenarrow band.
 15. The apparatus of claim 11, wherein a size of the one ormore proximate resource blocks is based on a power factor.
 16. Annon-transitory computer-readable medium storing computer code executableby a processor for wireless communications, comprising code for:determining at least one narrow band for transmission of a cell-specificreference signal (CRS) to a user equipment (UE); identifying one or moreresource blocks proximate the at least one narrow band; and transmittingthe CRS on the narrow band and the one or more proximate resource blocksto the UE.
 17. The non-transitory computer-readable medium of claim 16,wherein the at least one narrow band corresponds to a defined number ofresource blocks allocated for CRS transmission.
 18. The non-transitorycomputer-readable medium of claim 17, wherein the one or more proximateresource blocks are adjacent to the defined number of resource blocksforming the narrow band.
 19. The non-transitory computer-readable mediumof claim 18, wherein the one or more proximate resource blocks areadjacent to the defined number of resource blocks on at least one sideof the at least one narrow band.
 20. The non-transitorycomputer-readable medium of claim 16, wherein a size of the one or moreproximate resource blocks is based on a power factor.